We get a lot of contact from people who say that at odd times they get a bunch of old emails through- and sometimes multiple times, leading to doubling or tripling of each message. So what to do?
First we need to look at how email works between client and server. When you have a POP3 account, your email client will contact the server at a user specified time (say every 5 minutes) and the conversation goes something like this-
Hi I’m email@example.com
What’s your password?
Cool, you’re in
Do you have any new mail for me?
I’ve got email with message ID’s 32492048234, 2309423894238940, 230842490
Great, I don’t have those, please send them to me
Here you go >>> sending
OK I have received message with ID 32492048234, 2309423894238940, 230842490
I’ll mark them as sent
I’ll mark them as received, Thanks Bye
Notice those message ID’s? Every message has a unique number associated with it. Your email client keeps a cache of message ID’s so it knows which messages have been downloaded and which haven’t. And this is where the problem occurs.
Lot’s of things can make this fail. The client doesn’t mark the messages as received, the server doesn’t mark them as sent, the cache gets scrambled etc. The point here is that the system is designed with safety in mind- it will err on the side of caution and send you old messages again if it is not sure they were received.
Now- one big point here- the error generally exists on the client and NOT on the server. And you’ll notice that if you browse around your email client that you have NO access to any process to control this. This basically means that the problem is unfixable. And some email clients are worse than others. Here’s a helpful list for Mac email clients-
Microsoft Entourage (any version)- this product is deeply broken and you will have this problem sooner or later. Upgrade
Microsoft Outlook Mac (any version)- Microsoft claimed to have fixed the issue but didn’t. Time to upgrade.
Apple Mail- Doesn’t happen often, but does happen. You are probably not experiencing this issue
Other mail clients- Sorry, I don’t know.
So I apologise for being so unhelpful, but reality is that there is not much we can do about this problem. If you have any handy hints or updates on this issue, please contact me and I will update this post.